This thesis is about collaboration between geographically separated small enterprises and how they manage their collaborative efforts. The issue has been explored by studying how the collaborating colleagues handle references during telephone conversations. I have studied settings with very simple means for making references and for separated collaboration, where only telephone, computers with e-mail, faxes and ordinary mail are available for interaction. The reason for studying this simple setting is that these means are still quite commonly utilized among small businesses today. The character of the dissertation is quite empirical. How work is accomplished in practice is of primary interest. It is influenced by ethnomethodological studies about work, video analysis and conversation analysis, even though I don't wish to position it as either a thorough ethnography or a linguistic analysis. The empirical material consists of both interviews and observations. The interviews can be seen as a background for interpreting the collaborative situation between the companies and their partners. They also provide a picture about how those working in those settings experience their collaborative situation. Observations of work in action were made after the interviews and recorded on video. These interviews have been valuable when interpreting the observations and analyzing the videos. The interviews reveal that knowledge about your collaborators, their routines and communication is vital for the success of collaboration. Therefore, communication was studied more closely by using the records of work on video for how references were handled in collaborative sessions. Analysis of the videos told the same story as the interviews: knowledge about collaborators, their routines and their "world" were vital for collaboration in the geographically separated setting. References were made to what can be said to be old knowledge developed through previous common experiences and very little new references were made. Both the interviews and the analysis of the video clips also showed the importance of really sharing the material that was the object of the collaboration as soon as something needed to be discussed. The material was supposed to constitute similar worlds to refer to and to act upon, a substitute for the world they didn't share in reality. Through previous development of a common picture of this material and its content it was possible for the collaborators to talk about it and refer to it. At times when this common picture of the material and the environment was not established problems failed to be solved on distance and personal meetings were arranged. Personal meetings were also arranged when a task was new and undefined or if there was some kind of chaos. The persons in the videos also used more means to express themselves and to clarify their references than were mediated through technology. They also had to create their own private environments to be able to orient themselves to the references and explanations of their collaborators. Thus sharing an environment is necessary in order to be able to collaborate. This shared environment can, at times of geographically separated collaboration, be replaced by a shared picture of the environment, something that can be developed by previous shared experiences. New tasks, new environments or other undefined factors were not adequately established and defined for the collaborators to deal with by phone. It would be interesting to study how references were handled in settings with more advanced technology, allowing collaborators to share environment. There are already technologies that are developed for this purpose and studies about those technologies have been made. Unfortunately, most studies have been more interested in evaluating the technology than to study how collaborators handle references.